Methods and devices for occluding the ascending aorta and maintaining circulation of oxygenated blood in the patient when the patient&#39;s heart is arrested

ABSTRACT

A method and device for occluding a patient&#39;s ascending aorta, maintaining circulation of oxygenated blood in the patient and delivering cardioplegic fluid to arrest the patient&#39;s heart. An aortic occlusion catheter has an occluding member for occluding the ascending aorta. The aortic occlusion catheter passes through a cannula. Delivery of oxygenated blood is accomplished through either the cannula or the aortic occlusion catheter.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.09/012,833, filed Jan. 23, 1998, now U.S. Pat. No. 6,159,178, issuedDec. 12, 2000, the entire disclosure of which is hereby incorporated byreference.

BACKGROUND OF THE INVENTION

The present invention is directed to methods and devices for occluding apatient's ascending aorta and maintaining circulation of oxygenatedblood in the patient when the patient's heart is arrested. Such devicesand methods are useful for performing various procedures on a patient'svascular system and heart such as the procedures described in U.S. Pat.Nos. 5,584,803 and 5,682,906 which describe coronary artery bypassgrafting (CABG) and valve procedures, respectively. Another device andmethod for occluding a patient's ascending aorta is described in Re.35,352.

The methods and devices described in the above-mentioned patents use aninternal occlusion device to occlude the ascending aorta rather than aconventional external cross-clamp. Use of an internal occlusion devicemay reduce strokes as compared to conventional external cross-clampssince external cross-clamps distort and compress the aorta which mayrelease emboli leading to strokes.

It is an object of the invention to provide alternative methods anddevices for occluding a patient's ascending aorta and maintainingcirculation of oxygenated blood when the patient's heart is arrested.

SUMMARY OF THE INVENTION

In accordance with the object of the invention, the present inventionprovides alternative methods and devices for occluding a patient'sascending aorta and maintaining circulation of oxygenated blood in apatient when the patient's heart is arrested.

In a first preferred method and device of the present invention, anaortic occlusion device having a blood delivery lumen and an occludingmember is introduced into the patient's aortic arch. The occludingmember has an interior in fluid communication with the blood deliverylumen so that delivery of oxygenated blood inflates the occludingmember. An advantage of this method is that a separate inflation lumenis not necessary. The aortic occlusion device preferably passes througha cannula having a y-arm with the aortic occlusion catheter passingthrough an arm of the y-arm. The other arm of the y-arm connector iscoupled to the source of oxygenated blood so that bypass support can bemaintained even when the aortic occlusion device has been removed.

In another preferred method and device, oxygenated blood is delivered tothe patient through the aortic occlusion catheter. The aortic occlusioncatheter also passes through a cannula with a y-arm connector so thatbypass support can be maintained when the aortic occlusion device isremoved. The aortic occlusion device also preferably includes a lumenfor delivering cardioplegic fluid and venting the ascending aorta and apressure lumen for measuring pressure in the ascending aorta. If thelumens are not provided in the aortic occlusion device, delivery ofcardioplegic fluid, venting of the ascending aorta and pressuremonitoring may be accomplished with the cannula.

In another preferred device, the aortic occlusion device has anoccluding member mounted to a side of the catheter. The occluding memberhas a pathway therethrough which is in communication with a lumen in theaortic occlusion catheter. The pathway directs cardioplegic fluid towardthe coronary ostia while the aortic occlusion device directs theoxygenated blood in the direction of normal blood flow in the aorta.

These and other aspects and advantages of the present invention willbecome apparent from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an aortic occlusion device;

FIG. 2 is a cross-sectional view of a first step in forming the aorticocclusion catheter of FIG. 1;

FIG. 3 is a cross-sectional view of the structure of FIG. 2 afterheating;

FIG. 4 is a cross-sectional view of a further step in forming the aorticocclusion catheter of FIG. 1;

FIG. 5 is a cross-sectional view of FIG. 1 along line I—I;

FIG. 6 shows a cannula;

FIG. 7 shows an enlarged view of the distal end of the cannula of FIG.6;

FIG. 8 is a plan view of a ring;

FIG. 9 is a side view of the ring;

FIG. 10 shows a n introducer with an incising element in a retractedposition;

FIG. 11 shows the introducer with the incising element in an exposedposition;

FIG. 12 shows the aortic occlusion device and cannula passing through apenetration in the ascending aorta;

FIG. 13 shows another aortic occlusion device passing through thecannula and into the patient's ascending aorta;

FIG. 14 shows yet another aortic occlusion device;

FIG. 15 shows still another aortic occlusion device;

FIG. 16 shows a final aortic occlusion device;

FIG. 17 illustrates a preferred method of introducing the aorticocclusion device;

FIG. 18 shows another preferred aortic occlusion device with the balloonoccluding the ascending aorta; and

FIG. 19 shows the aortic occlusion device of FIG. 18 with the balloondeflated.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1 and 5, an aortic occlusion device 2 is shown. Theaortic occlusion device 2 has an occluding member 4 configured toocclude a patient's ascending aorta. The occluding member 4 ispreferably a balloon but may also be a mechanically actuated member. Theaortic occlusion device 2 has an inflation lumen 6 for inflating theoccluding member 4, a pressure lumen 8 for measuring pressure in theascending aorta, and a lumen 10 for delivering cardioplegic fluid and/orventing the ascending aorta. The aortic occlusion device 2 is preferablymanufactured and used in the manner described in U.S. patent applicationSer. No. 08/782,113 but may also be manufactured in any other mannersuch as an extrusion.

The aortic occlusion device 2 is preferably substantially straight in anunbiased position, however, the aortic occlusion device 2 may also havea shaped end. For example, the aortic occlusion catheter 2 can have anL-shaped end which facilitates positioning the occluding member 4 in theascending aorta depending upon the surgical approach. The aorticocclusion device 2 is preferably flexible so that it can be bent asnecessary without kinking.

Referring to FIGS. 2-5, a preferred method of forming the aorticocclusion device 2 is shown. FIG. 2 shows a longitudinal cross-sectionof a tube 12, preferably a urethane tube, mounted on a teflon-coatedmandrel 14 with the elongate element 16 wound helically around the tube12. The elongate element 16 is preferably a wire ribbon having athickness of 0.003 inch and a width of 0.012 inch. The elongate element16 is preferably wrapped around the tube 12 with a spacing of 0.010inch. Another tube 20 is positioned over the elongate member 16 and ashrink tube (not shown) is positioned over the tube 20. The entirestructure is then heated to fuse the tubes together to form a reinforcedtube 22 which is shown in longitudinal cross-section in FIG. 3. Theresulting reinforced tube 22 preferably has an inner diameter of about0.100 inch and a wall thickness of about 0.010 inch.

Referring to FIG. 4, a two-lumen member 24 is positioned against thereinforced tube 22 and a shrink tube 26 is positioned around the member24 and reinforced tube 22. The two-lumen member 24 has the inflationlumen 6, which is used for inflating the occluding member 4, and thepressure lumen 8, which is used for pressure monitoring in the ascendingaorta. The two-lumen member 24 is preferably an extrusion having aD-shaped outer surface in cross-section. The member 24 and tube 22 arethen heated and the shrink tube 26 is removed to obtain the egg-shapedcross-sectional shape shown in FIG. 5. The cross-sectional shape ispreferably about 0.145 inch tall and 0.125 inch wide. The inflationlumen 6 is then pierced to provide an inflation path to the occludingmember 4 and the occluding member 4 is then mounted to the shaft.

Referring to FIGS. 6 and 7, a cannula 28 is shown which is used toreturn oxygenated blood to the patient when the patient's heart isarrested. The aortic occlusion device 2 is introduced into the patientthrough the cannula 28 as will be described below. The cannula 28 has ay-arm connector 30 with first and second arms 32, 34 with each coupledto a lumen 35. The second arm 34 has a hemostasis valve 36 which may beany hemostasis valve and is preferably a Thouy-Borst valve. The cannula28 has a reinforced body 38 which is preferably formed in the mannerdescribed in U.S. patent application Ser. No. 08/749,683, which ishereby incorporated by reference, however, any other method may be usedincluding extrusion. The distal end 40 of the cannula 28 is beveled andhas an open end 42 and two side ports 44 for infusing oxygenated bloodinto the patient. A radiopaque markers 45 are provided at the distal endfor visualization as discussed below.

Referring to FIGS. 6-9, a ring 46 is attached to the distal end 40 ofthe cannula 28. The ring 46 limits insertion of the cannula 28 into thevessel, stabilizes the cannula 28, and receives purse-string sutureswhich provide hemostasis around the cannula 28 when the cannula 28 ispositioned in a vessel. Referring to FIGS. 8 and 9, the ring 46 hasslots 48 which may receive purse-string sutures as will be describedbelow.

Referring to FIGS. 10 and 11, an introducer 50 is positioned in thecannula 28 to introduce the cannula 28 into a vessel. The introducer 50has a connector hub 51 which is received by the hemostasis valve 36 onthe second arm 32 of the cannula 28 to seal the space between theintroducer 50 and cannula 28. The introducer 50 has an incising element52 for incising the vessel into which the cannula 28 is introduced. Theincising element 52 is attached to a shaft 54 which is coupled to atrigger 56 for moving the incising element 52 from the retractedposition of FIG. 10 to the exposed position of FIG. 11. An o-ring seals58 the space between an outer housing 60 and the shaft 54. The incisingelement 52 is biased toward the retracted position by a spring 62 sothat the incising element 52 is only exposed when the trigger 56 isactuated. When introducing the cannula 28 into the vessel, the trigger56 is actuated to move the incising element 52 to the exposed position,the vessel is incised with the incising element 52 and the cannula 28 isinserted through the incision. As will be described below, one or morepurse-string sutures are then used to form a hemostatic seal around thecannula 28. The incising element 52 may be omitted if a separateincising device is used.

Referring to FIG. 12, the cannula 28 is positioned in a patient'sascending aorta with the aortic occlusion device 2 passing through thehemostasis valve 36 . Placement of the cannula 28 and aortic occlusiondevice 2 into the position of FIG. 12 is described below. Referring toFIGS. 5 and 12, the lumen 10 is coupled to a source of cardioplegicfluid 64, the inflation lumen 6 is coupled to a source of inflationfluid 66, and the pressure lumen 8 is coupled to the pressure monitor 68for measuring pressure in the ascending aorta. The lumen 10 is alsocoupled to a vacuum source 70 for venting the ascending aorta.

The first arm 32 of the cannula 28 is coupled to a source of oxygenatedblood 72 so that blood is delivered through the lumen 35 of the cannula28 with the blood passing through the annular area between the cannula28 and the aortic occlusion device 2. The oxygenated blood passingthrough the open end 42 of the cannula 28 is directed at the occludingmember 4 so that the oxygenated blood is not directed at the wall of theaorta. An advantage of directing the oxygenated blood at the occludingmember 4 is that the fluid is dispersed radially outward by theoccluding member 4 before coming into contact with the wall of theaorta. By directing the blood at the occluding member 4, rather than atthe wall of the aorta, the likelihood of releasing emboli from the wallof the aorta may be reduced. Oxygenated blood is also directed throughthe side ports 44 so that oxygenated blood is delivered to the patienteven if the occluding member 4 blocks the open end 42 of the cannula 28.

Referring to FIG. 13, another aortic occlusion device 2A is shown havinga balloon 76 which is inflated with the oxygenated blood delivered tothe patient. The aortic occlusion device 2A has a blood flow lumen 78which is fluidly coupled to the interior of the balloon 76 for inflatingthe balloon 76. Oxygenated blood is then delivered to the patientthrough an opening 80, preferably a number of openings, in the balloon76. An advantage of the aortic occlusion device 2A is that a separateinflation lumen is not required since occlusion is accomplished bysimply delivering oxygenated blood through the aortic occlusion device2A. The aortic occlusion device 2A may also include a pressure lumen 82for measuring pressure in the ascending aorta and a lumen 84 fordelivering cardioplege and venting the ascending aorta. The aorticocclusion device 2A is preferably formed in the manner described aboveexcept that the lumen 78 is sized large enough to provide sufficientflow of oxygenated blood at an acceptable pressure. Acceptable bloodflow rates and pressures are disclosed in the above-mentioned patentsand patent applications which have been incorporated by reference.Although it is preferred to manufacture the device in the mannerdescribed above, the aortic occlusion device 2A may also simply be anextrusion or laminated structure. The balloon 76 is preferably made ofsilicone having a thickness of between 0.005 and 0.009 inch.

The aortic occlusion catheter 2A passes through the cannula 28 so thatoxygenated blood can be delivered to the patient when the aorticocclusion device 2A is removed. The cannula 28 is preferably the cannula28 described above with the first arm 32 coupled to the source ofoxygenated blood 72, pressure monitor 68, and source of cardioplegicfluid via valve 86. Thus, cardioplegic fluid and oxygenated blood can bedirected through the lumen 35 in the cannula 28 if the lumen 84 is notprovided in the aortic occlusion catheter 2A. The cannula 28 has thehemostasis valve 36 to seal the space between the cannula 28 and aorticocclusion device 2A.

Referring to FIG. 14, yet another aortic occlusion device 2B is shown.The aortic occlusion device 2B has the occluding member 4 and theinflation lumen 6 coupled to the source of inflation fluid 66 forinflating the occluding member 4. The aortic occlusion device 2B alsohas a lumen 88 for delivering oxygenated blood to the patient from thesource of oxygenated blood 64. The shaft is preferably reinforced with awire in the manner described above except that the lumen 88 is sizedlarge enough to provide adequate blood flow to the patient at anacceptable pressure as discussed above. The cannula 28 is preferably thesame as the cannula 28 described above and the aortic occlusion device2B is introduced through the cannula 28 in the manner described below.The first arm 34 of the cannula 28 has the hemostasis valve 36 forreceiving the aortic occlusion device 2B. The second arm 32 is coupledto a valve 90 which determines whether cardioplegic fluid or oxygenatedblood is delivered through the lumen 35 in the cannula 28. Valve 92determines whether oxygenated blood is delivered through the lumen 35 inthe cannula 28 or the lumen 88 in the aortic occlusion device 2B. Anadvantage of the aortic occlusion device 2B and cannula 28 is thatbypass support can be provided before inflating the occluding member 4and can also be maintained after the aortic occlusion device 2B isremoved from the cannula 28.

Referring to FIGS. 15, another aortic occlusion device 2C is shown. Theaortic occlusion device 2C has a balloon 94 mounted to a side of a shaft96. The aortic occlusion device 2C has an inflation lumen 98 forinflating the balloon 94 through inflation outlet 100 and a lumen 102for delivering cardioplegic fluid from the source of cardioplegic fluid64 and venting the ascending aorta using the vacuum source 70. Theaortic occlusion device 2C also has a blood flow lumen 104 fordelivering oxygenated blood to the patient from the source of oxygenatedblood 72. A fluid path 106 passes through the balloon 94 which is influid communication with the lumen 102 so that cardioplegic fluid isdelivered through the fluid path 106 in the balloon 94. An advantage ofthe aortic occlusion device 2C is that the cardioplegic fluid can bedelivered toward the aortic valve while oxygenated blood is directed inthe direction of normal blood flow in the aortic arch. The distal end ofthe aortic occlusion device has an open end 108 and side ports 110through which the oxygenated blood is delivered. The aortic occlusiondevice 2C also includes the ring 46 which is the same as the ring 46described above. The aortic occlusion device 2C may be manufactured inany manner such as the manner described above or as a simple extrusionor laminated structure.

Referring to FIG. 16, the aortic occlusion device 2 is shown passingthrough a side port 112 of a cannula 28D. The side port 112 facilitatespositioning the occluding member 4 in the ascending aorta. The aorticocclusion device 2 is preferably the aortic occlusion device 2 describedabove. The aortic occlusion device 2 passes through a lumen 114 in thecannula 28D. The lumen 114 is coupled to the source of oxygenated blood72 so that the oxygenated blood is delivered through the annular areabetween the aortic occlusion device 2 and the wall of the lumen 114. Thelumen 114 has an open end 116 with a cross-member 118 which prevents theaortic occlusion catheter 2 from passing through the open end 116. Anadvantage of the side port 112 is that the aortic occlusion device 2 isdirected into the ascending aorta while blood passing through the lumen114 is directed in the direction of normal blood flow in the aorta.

Referring to FIGS. 18 and 19, another aortic occlusion device 2E isshown. The aortic occlusion device 2E is similar to the aortic occlusiondevice 2A of FIG. 13 in that balloon 130 is inflated with oxygenatedblood delivered from the source of oxygenated blood 72. Oxygenated bloodis delivered to the patient through a lumen 132 and an open end 134 ofthe aortic occlusion device 2E. As will be described below, the interiorof the balloon 130 is fluidly coupled to the lumen 132 through aninflation hole 133 for inflating the balloon 130 when blood is deliveredthrough the lumen 132.

The aortic occlusion device 2E includes a body 136 having the y-armconnector 30 described above. A sleeve 138 is positioned in the lumen132 to control inflation and deflation of the balloon 130. Blood passingthrough the lumen 132 passes through the sleeve 138 so that the sleeve138 does not interfere with delivery of oxygenated blood to the patient.The sleeve 138 is attached to a rod 140 which is manipulated to move thesleeve 138 between the positions of FIGS. 18 and 19. The sleeve 138 hasa hole 142 which is aligned with the inflation hole 133 as shown in FIG.18 to fluidly couple the interior of the balloon 130 with the lumen 132.When the sleeve 138 is advanced to the position of FIG. 19, the hole 142is not aligned with the inflation lumen 133 and the sleeve 138 coversthe inflation hole 133 so that the interior of the balloon 130 is notfluidly coupled to the lumen 132.

The sleeve 138 permits the surgeon to control inflation and deflation ofthe balloon 130. After introduction of the aortic occlusion device 2E,bypass support is generally initiated before inflating the balloon 130.This can be accomplished by maintaining the sleeve 138 in the positionof FIG. 19 so that the balloon 130 is not inflated by the blooddelivered through the lumen 132. When it is desired to inflate theballoon 130 and occlude the ascending aorta, the sleeve 138 is moved tothe position of FIG. 18 so that the balloon 130 is inflated with blood.The sleeve 138 also permits the surgeon to maintain full occlusion ofthe ascending aorta even when blood flow is reduced to a level whichwould not provide sufficient pressure to inflate the balloon to maintainfull occlusion of the aorta. In order to maintain occlusion at low flowrates, the sleeve 138 is moved to the position of FIG. 19 beforereducing the blood flow rate so that the balloon 130 will remaininflated when the delivery pressure drops. Finally, the sleeve 138 alsopermits the surgeon to maintain bypass support with a deflated balloon130 after the surgical procedure is completed. In order to maintaindeflation of the balloon while delivering blood, the blood flow rate isreduced to deflate the balloon 130, the sleeve is moved to the positionof FIG. 19 to deflate the balloon, and the blood flow rate is thenincreased. The sleeve 138 prevents the balloon 130 from inflating whenthe blood flow rate is increased.

The body 136 may be made in any suitable manner and is preferablymanufactured similar to the cannula 28 of FIG. 6. A support tube 144 isattached to the body and the balloon 130 is mounted to the support tube.A soft tip 145 is attached to the distal end of the support tube 144 toprovide an a traumatic distal end to prevent injury during introductionof the device 2E. The sleeve 138 may be made of any suitable materialand is preferably a urethane tube. The rod 140 may also be made of anysuitable material and is preferably urethane coated polyamide. Althoughit is preferred to provide the sleeve 138 between the interior of theballoon 130 and the lumen 132 any other device may be used such as avalve, balloon or plug.

Use of the cannula and aortic occlusion device 2 is now described inconnection with FIGS. 12 and 17. The description below is applicable toall cannulae 28, 28D and aortic occlusion devices 2, 2A, 2B, 2Cdescribed herein. Although the method described below is for directinsertion of the cannula 28 and aortic occlusion device 2 into theaortic arch, the cannula 28 and aortic occlusion device 2 may also beintroduced through a peripheral artery such as the femoral, subclavianor axillary arteries as described in U.S. Pat. No. 5,484,803.

Before introduction of the cannula, a rib retractor 120 or other deviceis used to form an opening in an intercostal space such as the 4^(th)intercostal space. The opening through the intercostal space is used foraccess to perform a surgical procedure such as a valve repair orreplacement. The opening also provides direct access to the ascendingaorta for control of the ascending aorta and to place purse-stringsutures in the aorta.

An incision is also created in the 1^(st) or 2^(nd) intercostal space inwhich an 11.5 mm trocar 122 is positioned. The cannula 28 is thenintroduced through the trocar 122 and advanced to the surface of theaorta with the introducer 50 (see FIGS. 10 and 11) positioned in thelumen 35 of the cannula 28 to determine the appropriate orientation ofthe cannula 28. The distal end of the introducer 50 is then moved intocontact with the aorta about 1-2 cm below the origin of the innominateartery to identify the appropriate location for purse-string sutures124. The surgeon then places two purse-string sutures 124 around thesite. The ends of the purse-string sutures 124 are passed through tubes126 which are used to tension the purse-string sutures 124. Thepurse-string sutures 124 are then passed through the slots 48 in thering 46.

The cannula 28 is then advanced into contact with the aorta at the sitenow surrounded by the purse-string sutures 124. The surgeon then incisesthe aorta with the incising element 52 of the introducer 50 or with aseparate incising instrument. The cannula 28 is then immediatelyadvanced through the incision until the ring 46 engages the aorta. Theradiopaque marker 45 may be viewed under fluoroscopy and the cannula 28manipulated until the beveled tip is directed toward the aortic valve.Alternatively, the tip orientation may be determined by TEE. Thepurse-string 124 sutures are then tensioned to seal around the cannula28. The aortic occlusion device 2 is then passed through the hemostasisvalve 36 and advanced until the occluding member 4 is positioned in theascending aorta. Delivery of oxygenated blood, occlusion of theascending aorta and delivery of cardioplegic fluid is then performed inthe manner described in U.S. Pat. No. 5,484,803.

Although the method described above positions the aortic occlusiondevice through an opening separate from the opening through which thesurgeon operates, the cannula and aortic occlusion device 2 may also beintroduced through the same opening through which the surgeon operates.The choice of opening location, number and size are a matter of surgicalchoice depending upon patient anatomy, the medical procedure beingperformed, surgeon preference and the particular embodiment of theinvention being used. Furthermore, the devices described herein may haveapplication in other parts of the heart and in other parts of the body.Thus, the description of the specific procedure described above ismerely an example and other surgical methods may be used with thedevices and methods of the present invention.

What is claimed is:
 1. A system for occluding a patient's ascendingaorta and delivering oxygenated blood to the patient, comprising: acannula having a first lumen and a second lumen, the first lumen havinga distal end for delivering oxygenated blood; an occluding membermounted to one side of the cannula at a location proximal the distalend, the occluding member being movable between a collapsed position andan expanded position, the occluding member having a pathway therethroughin fluid communication with the second lumen, wherein the occludingmember is a balloon.
 2. The system of claim 1, wherein the occludingmember is configured to occlude the aorta at a location between thebarchiocephalic arteries and the coronary ostia.
 3. The system of claim2, wherein the occluding member is configured such that the cannula islocated between the occluding member and the brachiocephalic arterieswhen the occluding member occludes the aorta at a location between thebrachiocephalic arteries and the coronary ostia.
 4. The system of claim1, wherein the cannula has a third lumen in fluid communication with theinterior of the occluding member.
 5. The system of claim 4, comprising asource of cardioplegia fluid coupled to the second lumen.
 6. The systemof claim 1, comprising a source of oxygenated blood coupled to the firstlumen.
 7. The system of claim 1, wherein the distal end of the cannulahas side ports.